Switch or circuit-changer



BESTAVAILABLE COP (N0 Mo dl.) 2 Sheets-Sheet 1.

. W. W. GRISOOM.

SWITOH 0R CIRCUIT CHANGER.

' No. 393,365. Patented Nov. 27, 1888.

BEST AVAILABLE COP (No Model.) 2 Sheets-Sheet W. W. GRISCOM.

SWITGHOR CIRCUIT CHANGER.

.No. 393,365. Patented Nov. 27, 1888.

)Vi-t-meoaw,

BEST AVAILABLE COP UNITED STATES PATENT -OFFICE \VILLIAM W. GRISCOM, OF HAVERFORD COLLEGE, PE NN$YI..-VANIA.

.SWITCH R CIRCUIT-CHANGER.

SPECIFICATION forming part of Letters Patent No. 393,365jdatd November 27, 1888.

Application died June 80. 1888. Serial No. 278.088. (No model.)

To all whom it may concern:

Be it known that I, VVILLIAM W. GRl'SCOM, acitizen of the United States, and a resident of Haverford College, in the county of Montgomery audState of Pennsylvania, have invented certain new and useful Improvements in Switchcsor Circuit-Changers, of which the following is'a specification.

Myinvention is an improvement in switches or circuitclosers.

The object is to provide a switch that shall make contact more certainly and avoid the iu-- troduction of additional resistance, while the construction of the switch is mechanically stronger and moredurable than anything heretofore known or used.

Prior to my invention it was not possible to produce a satisfactory switch of this description for operationsvith. currents. of. great .intensity. sired conductivity and-to possess many other Castbrassis found-to furnish the devalnable qualities; but heretofore when the vproper extent of surface contact was employed it was difficult or impossible to arrange two contacting surfaces which would always register with the same degree of friction and produce the same perfection of electrical contact, if, indeed, such a switch was not at times inoperative. I am by my invention enabled to utilize east-brass for switches of almost any extent of contact-surface and thus make use of its valuable properties by constructing the contacting surfaces in two or more divisions each,

thus dividing the necessary spring between several branches, all of which contribute to increase the conductivity. The definite relation existing between the cast brass and the special formof switch devised by me enables the at- I each of which consists of a casting havinga bifurcated free te'rminal,the space between the.

two branches thereof being just sufficient to admit the two branches of the first-named'or.

rotating contact. The two branches of both contacts are thus given a spring,and both are thus caused to yield when coming into contact. It is this particular feature which reuders this construction possible and which gives the beneficial results derived from the use of my switch, for I can thus make both branches of both bifurcations of greater strength and rigidity and greater conductivity than is the case with instruments of a similar nature heretofore invented, and when coming together all four contact-s .yicld or spring sufficiently to make a complete gripping contact possiblethat-is to say, divide up the necessary spring or movement among four branches, instead of confining it to one or two branches, as heretofore. g 1 The accompanying drawings illustrate my invention...

Fignrel is thesimplest form'of construct-ion showingrny improvements. I Fig. 2 is a crosssection at line 2 2, Fig. 1. Fig. 3 is a modification embodying the same improvemcntsmml Fig. 4 is a cross-section on theline 4, 4, Fig. 3.

In Fig. 1, b -isa base-board of insulating material. A isa casting of brass. a and a are bifurcations thereof having considerable rigidity and butlittlc spring. Casting A is me ehanieally connectcdor fixed to spindle f and has bearings in the base-board 0, thus providing for a movement of rotation. Located near to the center of movement in a circumference the radius of which is about equal to the length of the bifurcated arm Aare twohrass castings, B B. .lslach casting B Bhas' a bifureation,c c, Fig. 2. The space separating c and c is about equal to the distance from the upper surface of a: to the under surface of a, so that'the bifurcated contact an may enter between the bifurcations o c, and the slight spring 'possesscdby each division a a cc fnruishcsa'gcueral movement orspringsnfiicient to admit one pairof bifurcations between the second or com plemeut-' 4 my pair. The castings'A- and B are provided with cylindrical holes 8 and screws for clamping the ends of' the electric circuits into position, as is well known. I

In Figs. 3 and. 4the same improvements are embodied; but there is provision made for a double-pole circuit-changer, the castings A and A being-inytwo main 1cads,'rcspect1vely,

What; 1' claim, and desire to secure hy Lets tors Patent, is.

1. In a switch or circuit-changer, the combination of two bifurcated castings of metal forming t-hetwo terminzilsof adivided circuit, the bifurcations of one terminal entering ,be-

tween the bifiircations of the second, whereby 1 extended surfaces are placed in Contact under spring-pressure, substantially as described.

2. The combination, in a switch or circuit- BEST AVAILABLE COP" changer, 0; 2L bifismitel cesiizzg fiz-zeii 0 a reizuy bearing in 1: base of insulciing material and forming one terminal of a divided circuit, and One or were bifurcated castings fixed in pesition in a circumferential lineef which said arm forms the radius said cps-tings being insulated from each other and forming complemerimry contacts for said arm,the bifurentioiis ul'ui'ie casting entering bet-ween the bifurcat-iens in the other, snbstanL-iaiiy as described. 25

l. W. GRISCOM.-

Witnesses:

' DANIEL DEL-WAX.

W. B. VANSIZE. 

